290 Mr . Bennet’s Defcriptwn of 
the fecond plate by its mfulating handle, and if the electricity 
be not now fenfible by the electrometer, I place the third plate, 
by means of its mfulating handle, upon the fecond plate, thus 
elevated: then touching the third plate, by firetching a huger 
over the juncture of its inhibiting handle, and again with- 
drawing the finger, 1 then again feparate the third plate from 
the fecond. In this fituation it will be apparent to electricians 
that two of the 'plate-s are of one kind of eleCtricity, and 
nearly of equal quantity, and one only of the other. I then 
apply the third plate to touch the under furface of the firft 
plate which remains on the electrometer, and at the fame time 
covering the firft plate with the fecond, I then touch the fecond 
plate by firetching a finger over the juncture of its infulating 
ha idle ; and firft taking away the third plate, and then with- 
drawing my finger from the fecond, and lifting it up from the 
firft plate, the eleCtricity becomes doubled. If by this firft 
operation the quantity of eleCtricity does not become fen- 
fible by the electrometer, I repeat the procefs to ten or 
twenty times, which, by doubling it every time, makes vifible 
the fmalleft conceivable quantity of eleCtricity, fince, at the 
twentieth operation, it is augmented to above 500,000 times. 
And though in defcription the above procefs of doubling to 
twenty times may appear tedious, yet when the operator can 
perform it with fufficient readinefs (which is foon acquired) 
it takes lefs time than 40 feconds. The collection of eleCtricity 
from the air, and the touching and pofition of the plates, are 
reprefented in Tab. XI figures 1. 2. 3. 4. 5. and 6. 
If it be required to produce fparks, the plates are to be 
placed upon an infulating ftand, without an electrometer, and 
the procefs repeated as above till the fparks appear. 
The experiment which proves that the eleCtricity is doubled 
by each operation is this. If the two flips of pendulous leaf 
gold 
